Throughout industry and within the home, a need exists for tools that can be safely used within wet environments. This is particularly true of areas in and around swimming pools where a high risk of electrical shock exists with the utilization of conventional power tools.
Water driven rotational tools are known in the prior art. U.S. Pat. No. 1,905,424 issued to R. Schlieper, dated Apr. 25, 1933, shows a water driven washing apparatus which is a cleaning apparatus for cars that uses pressurized water supplied via a garden hose to provide rotary motion to a sponge. The exhausting water is deflected downwardly through a disc having a plurality of apertures into a sponge that is used to wash a vehicle.
U.S. Pat. No. 4,193,228 issued to Bowler, dated Mar. 18, 1980, provides a water-driven tool that can be used for polishing tile around a swimming pool or shower in a wet environment.
U.S. Pat. No. 4,463,525 issued to Sheber, dated Aug. 7, 1984, shows a hand-held cleaning tool with a remote water turbine power source contained in a floating housing. The outlet of the water turbine is connected to one end of a suction hose. A flexible drive cable assembly has one end connected to the cleaning tool and the other end connected to the water turbine.
U.S. Pat. No. 5,620,364 issued to Torrance et al., dated Apr. 15, 1997, shows a hand-held water-driven rotary tool. The tool uses water pressure to drive an internal impeller and reducer gear to create the torque required for use. A major drawback of this device is the requirement of an internal gear-train. The impeller must rotate at about 20,000 RPM to create the torque necessary to spin the cutting disc at 3,000 to 4,000 RPM, which is the required speed necessary to complete an ordinary job. The heat generated at 20,000 RPM tends to wear down the internal bearings which can ultimately lead to the bearing spinning faster than the shaft. This decreases the torque, creating cavitation, internal damage and insufficient performance.
U.S. Pat. No. 6,203,415 issued to Torrance-Castanza et al., dated Mar. 20, 2001, shows a direct-drive, water-driven rotary tool. The device includes a housing having a central cavity, an impeller with angled, beveled blades around its periphery, a drive shaft connected to a rotatable mounting pad or backing pad that contains a disc with a grinding or sanding surface that is removably attached thereto. The device also includes a high pressure water inlet conduit having a changeable nozzle to allow using the tool with different water sources to maintain a constant RPM. The water exiting the nozzle strikes the blades of the impeller, rotating the impeller, which rotates the backing pad and sanding disc. Exhausting water is diverted downwardly through a bearing mounting plate having holes that allows the expended water from the impeller to be expelled peripherally around the outside of the main cavity of the housing. The device also includes a manually-actuated trigger for the inlet water valve which can be held at the same time as a D-shaped handle affixed directly on the housing.
While the prior art devices are suitable for use in wet environments, they include numerous drawbacks. One such drawback has prevented the prior art devices from use in heavy duty applications. The drawback relates to the torque the prior art devices are capable of developing. Grinding soft surfaces or washing the paint on a vehicle only requires a small amount of torque to complete the task. However, heavy duty applications, such as grinding hard materials, e.g. granite or structural concrete, requires significantly more torque. The impeller constructions of the prior art typically utilize an impeller which has a single side plate. The single side plate includes a plurality of upwardly projecting curved blades which the water is impacted against. This construction does not adequately control the flow path of high pressure water. The single side plate allows the water to flow over the top of the blades to impact opposing blades causing drag on the impeller. The result is reduced efficiency and reduced torque.
Another problem with the devices shown in the prior art is that they do not sufficiently control the exhausting water. The failure to control the exhausting water prevents their use in environments that must be kept substantially dry. For example, it is becoming common to cast counter tops from structural concrete. The counter tops are cast in place within the home. After casting, the concrete requires grinding and polishing to create a suitable surface finish for home interiors. The devices shown by Torrance-Castanza exhaust water in a generally uncontrolled manner through a plurality of apertures in the lower portion of the device. The water is directed downwardly around the entire periphery of the device onto the backing pad. The backing pad spins at a high rate of speed causing the exhausted water to spray outwardly throughout a large circumference, making this construction unsuitable for working in environments which must be kept substantially dry.
The present invention overcomes these problems by providing a high torque water-driven tool which provides a controlled exhaust. The device includes a hydrodynamically designed impeller within a hydrodynamically designed housing to provide substantially increased control of water flow when compared to the prior art. The controlled flow of high pressure water through the motor provides increased efficiency and directed exhaust. The device can be specially adapted for a plurality of uses within a wet environment such as a pool where it would not be practical to provide electrical power directly to the tool due to the dangers of electrocution. The device can also be utilized within closed generally dry environments without the destructive over-spray of the prior art. The grinding device may be utilized for grinding or polishing stones, cement, fiberglass, and even wood and metal surfaces.
Also, from a versatility standpoint, the assembled device is lightweight and easily manipulated. The device includes at least one fixed handgrip for tasks in close proximity to the operator. The device accommodates an extendable handle which permits a complete range of articulation for tasks which require extended operator reach.
There are also commercial considerations that are satisfied by the viable water driven rotary tool device; considerations which are not entirely satisfied by state of the art products. The water driven rotary tool is formed of relatively few component parts that are inexpensive to manufacture by conventional techniques. In addition, the device components are formed of corrosion resistant materials for long useful life.